Being in South Georgia I see this a lot.
Being from the northern great lakes region I know what minus zero temperatures can do and I know broken sprinklers can do millions of dollars in damages.
I am constantly amazed the risks sprinkler contractors will take to "save" a customer $2000 by not installing an anti-freeze or dry system in certain areas but around here "it never gets cold enough to freeze".
I got news for them. Valdosta, Georgia the highest recorded temperature was 108°F in 1927. On average, the coolest month is January. The lowest recorded temperature was 2°F in 1899.
You get 2 degrees for 12 hours and you will have severe troubles. Sure, hasn't happened since 1899 but it has happened and the good book doesn't tell me it won't come next January.
We get 2 degrees around here and I'll have enough repair work to keep me busy for the next year.
For Las Vegas the lowest recorded temperature was 0°F in 1963. At zero it is going to freeze and while that zero record might not happen for a long time to come as sure as the sun rises you can be sure it will be broken again someday. Maybe next January.
I wouldn't want to do it unless I got a PE to give me a letter, signed and sealed, stating he did a heat study and it wouldn't freeze. I don't think any of you PE's the frequent here would give such a letter so why should I take the risk?
Completed operations insurance for sprinkler companies is high to begin with, it's getting harder to obtain and if you ask any of them their biggest loss is water damage resulting from "improperly installed sprinklers".
I don't get it. Why take the risk when there isn't anything in it for you but work on a stinking job worth only a few thousand to begin with?
To the defense of inspector's and fire officials I don't think it should be their call as to what kind of system you install. They don't perform heat studies, precious few are professional engineers and non of them have the experience installing companies and layout technicians have.
There's a project down here the installation company took a bet their pipe would never freeze. It might not but the lowest recorded temperature was 30 below freezing in 1985. I'm just watching because IF it ever does freeze it's going to cause millions and millions in damages. In one area they have three original oil paintings that are valued over $2 million. Someone would probably notice the black spatter of rusty sprinkler water.....
Sorry I got carried away but it is important our industry stop taking unnecessary risks. You got enough of them without asking for more.